convertLongMonthDayToShort.test.ts

import { convertLongMonthDayToShort } from "server/domain/client/convertLongMonthDayToShort";

describe("convertLongMonthDayToShort", () => {
  it.each([
    [undefined, undefined],
    [null, null],
    ["1/1", "1/1"],
    ["8/31", "8/31"],
    ["3/31", "3/31"],
    ["4/30", "4/30"],
    ["12/31", "12/31"],
    ["01/31", "01/31"],
    ["02/28", "02/28"],
    ["08/31", "08/31"],
    ["07/31", "07/31"],
    ["10.31", "10/31"],
    ["09/30", "09/30"],
    ["03/31", "03/31"],
    ["07/01", "07/01"],
    ["10/31", "10/31"],
    ["06/30", "06/30"],
    ["05/31", "05/31"],
    // ======
    ["04/30/2024", "04/30"],
    ["8/31/24", "8/31"],
    ["7/31/2024", "7/31"],
    ["7/31/2023", "7/31"],
    ["09/30/2023", "09/30"],
    ["09/30/2024", "09/30"],
    ["12/31/2023", "12/31"],
    ["12/12/2023", "12/12"],
    // ======
    ["5-31-2024", "5/31"],
    ["12-31-2023", "12/31"],
    // ======
    ["May 31", "5/31"],
    ["Oct 31", "10/31"],
    ["Dec 31", "12/31"],
    // // ======
    ["Dec. 31", "12/31"],
    // // ======
    ["January 31", "1/31"],
    ["February 28", "2/28"],
    ["March 30", "3/30"],
    ["March 31", "3/31"],
    ["April 30", "4/30"],
    ["June 30", "6/30"],
    ["July 31", "7/31"],
    ["August 31", "8/31"],
    ["September 30", "9/30"],
    ["October 31", "10/31"],
    ["November 30", "11/30"],
    ["December 31", "12/31"],
    // // ======
    ["August 31st", "8/31"],
    ["December 31st ", "12/31"],
    // // ======
    ["December31", "12/31"],
    // // ======
    ["December, 31", "12/31"],
  ])("%s -> %s", (input, expected) => {
    const actual = convertLongMonthDayToShort(input);
    expect(actual).toBe(expected);
  });

  it.failing.each([
    // ======
    ["9/31/2024", ""],
    ["11/31", ""],
    ["December", ""],
    ["April 2024", ""],
    ["December 2023", ""],
    ["September 30th", ""],
  ])("invalid: %s -> %s", (input, expected) => {
    const actual = convertLongMonthDayToShort(input);
    expect(actual).toBe(expected);
  });
});

convertLongMonthDayToShort.ts

import { monthDaySchema } from "shared/validation/client";

export function convertLongMonthDayToShort(monthDayRaw: string | null | undefined) {
  if (monthDayRaw == null) return monthDayRaw;

  let monthDay = monthDayRaw.trim();

  // Mar 31
  // Mar. 31
  // March 31
  // March 31st
  // March, 31
  // March, 31st
  // March31
  const regex1 = /^(?<month>[A-Za-z]+)(\.?|,?)\s*(?<day>\d+)(\w)*$/;
  if (regex1.test(monthDay)) {
    const months = [
      "Jan",
      "Feb",
      "Mar",
      "Apr",
      "May",
      "Jun",
      "Jul",
      "Aug",
      "Sep",
      "Oct",
      "Nov",
      "Dec",
    ];
    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- guaranteed to not be null
    const groups = monthDay.match(regex1)!.groups!;
    const monthShort = groups.month.slice(0, 3);
    const monthIndex = months.indexOf(monthShort) + 1;

    monthDay = `${monthIndex}/${groups.day}`;
  }

  // 3/30
  // 03/30
  // 3.30
  // 03.30
  const regex2 = /^(?<month>\d{1,2})(\/|\.|-)(?<day>\d{1,2})\/?/;
  if (regex2.test(monthDay)) {
    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- guaranteed to not be null
    const groups = monthDay.match(regex2)!.groups!;
    monthDay = `${groups.month}/${groups.day}`;

    const isValid = monthDaySchema.isValidSync(monthDay);
    if (isValid) return monthDay;
  }

  return "???";
}